Andrei M. Sarna-Wojcicki, Jefferey R. Knott, John A. Westgate, James R. Budahn, John Barron, Colin J. Bray, Greg A. Ludvigson, Charles E. Meyer, David M. Miller, Rick E. Otto, Nicholas J.G. Pearce, Charles C. Smith, Laura C. Walkup, Elmira Wan, James Yount

Ibex Hollow Tuff from ca. 12 Ma supereruption, southern Idaho, identified across North America, eastern Pacific Ocean, and Gulf of Mexico

  • Stratigraphy
  • Geology
Save to CiteDrive Show PDF

Abstract The Ibex Hollow Tuff, 12.08 ± 0.03 Ma (40Ar/39Ar), is a widespread tephra layer erupted from the Bruneau-Jarbidge volcanic field of southern Idaho. Tephra from this eruption was deposited across much of western and central North America and adjacent ocean areas. We identified the Ibex Hollow Tuff at Trapper Creek, Idaho, near its eruption site, and at 15 distal sites, from the Pacific Ocean to the Gulf of Mexico, by the chemical composition of its glass shards, using electron-microprobe analysis, instrumental neutron activation analysis, and laser-ablation–inductively coupled plasma–mass spectrometry. By these methods, we distinguished the Ibex Hollow Tuff from overlying and underlying tephra layers near its source and at distal sites. Fluvially reworked Ibex Hollow Tuff ash was transported by the ancestral Mississippi River drainage from the interior of the North American continent to the Gulf of Mexico, where it is present within an ~50-m-thick deposit in marine sediments in the subsurface. The minimum fallout area covered by the ash is ~2.7 million km2, with a minimum volume of ~800 km3, and potential dispersal farther to the north and northeast. The areal distribution for the Ibex Hollow Tuff is similar to that of the Lava Creek B (0.63 Ma) supereruption. The Ibex Hollow Tuff represents a unique chronostratigraphic marker allowing a synoptic view of paleoenvironments at a virtual moment in time across a large terrestrial and marine region. The Ibex Hollow Tuff is also an important marker bed for North American Land Mammal Ages, and it coincides with climatic cooling in the middle to late Miocene documented in marine cores.

Need a simple solution for managing your BibTeX entries? Explore CiteDrive!

  • Web-based, modern reference management
  • Collaborate and share with fellow researchers
  • Integration with Overleaf
  • Comprehensive BibTeX/BibLaTeX support
  • Save articles and websites directly from your browser
  • Search for new articles from a database of tens of millions of references
Try out CiteDrive

More from our Archive